Image acquisition and image processing for the intraocular vision aid.

The contribution describes an "intraocular vision aid (IOVA)" system for patients suffering from corneal opacification. In order to gain patients' acceptance the system has to be miniaturized to a magnitude that image acquisition, image processing, and power supply can be integrated into a portable unit. A CMOS camera whose dynamic range covers more than 100 dB takes pictures of the scenery. Its image sensor has a resolution of 380 x 300 pixel. In order to reduce fixed pattern noise correlated double sampling is implemented on-chip. In addition, this sensor stands out for low power consumption, random pixel access, and local brightness adaptation. An analog-digital-converter allows direct coupling to an external signal processor or a monolithically integrated unit for image processing to compress data.

Wireless power and data transmission system for a micro implantable intraocular vision aid.

Wireless power and data transmission system developed for an intraocular vision aid for blind patients will be described. This system is applicable for patients suffering from bilateral corneal opacification but with intact posterior ocular. The system consists of an external unit as well as an implant. The external unit is required for image acquisition, channel coding, IR data transmission, and RF power transmission to the implant. The implantable unit contains a CMOS receiver, a receiver antenna coil, and the microdisplay based on a LED array. The CMOS receiver serves for reception and decoding of image data as well as driving circuits for the miniaturized LED array. In this case, mechanical wiring between the external unit and the implant is neither useful nor comfortable. An optimal technical solution needs a wireless data transfer. If the power is transferred to the implant wireless, too, the solution grows ideal. The system described in this communication employs wireless power and data transmission using an 13.56 MHz RF link for power transmission and an near IR (NIR) optical link for data transmission from an external CMOS camera and telemetry unit to the implantable micro display.

Copper binding to the PrP isoforms: a putative marker of their conformation and function.

We show here that PrP(C), the normal isoform of the prion protein (PrP(Sc)), could be retained by a Cu(2+)-loaded resin through two different binding sites. Contrarily, PrP(Sc) was not retained at all by such resin. This constitutes a new prion-specific property of PrP(Sc), which in addition to protease resistance and beta-sheet content, may result from its aberrant conformation.

Diet and childhood asthma in a society in transition: a study in urban and rural Saudi Arabia.

BACKGROUND: The causes of the worldwide increases in asthma and allergic diseases in childhood, which seem to relate to increasing prosperity, are unknown. We have previously hypothesised that a reduction in the antioxidant component of the diet is an important factor. An investigation was undertaken of dietary and other risk factors for asthma in Saudi Arabia where major lifestyle differences and prevalences of allergic disease are found in different communities. METHODS: From a cross sectional study of 1444 children with a mean age of 12 (SD 1) years in Jeddah and a group of rural Saudi villages, we selected 114 cases with a history of asthma and wheeze in the last 12 months and 202 controls who had never complained of wheeze or asthma, as recorded on the ISAAC questionnaire. Risk factors for asthma and allergies (family history, social class, infections, immunisations, family size, and diet) were ascertained by questionnaire. Atopy was assessed by skin prick testing. RESULTS: In univariate analyses, family history, atopy, and eating at fast food outlets were significant risk factors for wheezy illness, as were the lowest intakes of milk and vegetables and of fibre, vitamin E, calcium, magnesium, sodium, and potassium. These differences were present also in the urban children considered separately. Sex, family size, social class, infections, and parental smoking showed no relationship to risk. In multiple logistic regression analysis, urban residence, positive skin tests, family history of allergic disease, and the lowest intakes of vitamin E, magnesium and sodium related significantly and independently to risk. The lowest tertile of intake of vitamin E was associated with a threefold (95% CI 1.38 to 6.50) increase in risk when adjusted for the other factors. Intake of milk and vegetables both showed inverse linear relationships to being a case. CONCLUSIONS: This study suggests that dietary factors during childhood are an important influence in determining the expression of wheezy illness, after allowing for urban/rural residence, sex, family history, and atopy. The findings are consistent with previous studies in adults and with the hypothesis that change in diet has been a determinant of the worldwide increases in asthma and allergies.

Asthma and respiratory symptoms in urban and rural Saudi Arabia.

The aim of this study was to contrast the prevalence of allergic symptoms in children living in urban and rural areas of Saudi Arabia and to investigate factors associated with any differences found. A cross-sectional questionnaire survey was conducted of a social class-stratified sample of 1,020 urban and 424 rural 12 yr old children, recording symptoms of current and past allergic disease and doctors' diagnoses, together with nationality and the fathers' educational level and occupations. A significantly greater prevalence of allergic symptoms was found in urban than in rural children and in Saudi than in non-Saudi Arab children. Males were more likely to have some respiratory symptoms and females had more eye and skin symptoms. Educational level and occupation of the father did not influence the likelihood of having symptoms. Logistic regression analyses showed that urban residence and Saudi nationality were the two main risk factors associated with asthmatic symptoms. There is likely to have been a recent increase in the prevalence of allergic disease in Saudi children associated with increased affluence, which has not affected non-Saudi migrants moving into the same environment to the same extent. This is consistent with the hypothesis that the environment, possibly through changes in lifestyle and patterns of infection, influences the expression of allergic disease.

Ill-health and health-care in Khartoum/Omdurman.

Medical geographies of Third World cities are particularly affected by lack of data of sufficient detail and spatial resolution to allow proper analysis of intra-urban patterns of variation. Rapid rates of population growth fuelled both by natural increase and migration compound the problem of demographic accounting. Khartoum/Omdurman, the major urban complex in the Sudan is no exception to this situation and although some available statistical information from official sources is used to portray some of the characteristics of urban ill health, greater reliance is placed upon data collected during a social survey of seven contrasted residential areas. Whilst the extent of under-reporting of disease and the typical patterns of ill-health become apparent, it is also clear that there are very large differences among the different types of residential area. The gap between rich and poor, manifest in many criteria of social well-being, is also no less acute in terms of vulnerability to disease. It is also evident that although quality of services is generally problematic, something resembling an 'inverse-care' situation seems to exist which further exacerbates the disadvantage of poor urban dwellers.